Vibrations of piano strings are normally suppressed by dampers. Therefore, even if another string is struck, strings that are not struck do not vibrate. In contrast, when the dampers are separated from the strings by stepping on the damper pedal, strings resonate due to vibrations of another struck string. This resonance tone is very important in a piano.
In an electronic musical instrument, as a configuration that can reproduce sound like that during a performance while a damper pedal is depressed, there are a method in which piano tones during operation of the damper pedal are stored and read out (waveform readout), a method in which resonance is caused by delay loops corresponding to the fundamental pitch of input musical tones (delay loop), and other methods.